Graphical AbstractHighlights d SpiderMass technology collects molecular information ex vivo and in vivo d Tumor classification by typing and grading is obtained by the technology d Found markers are cross-validated with mass spectrometry imaging d The technology was assessed ex vivo at the vet surgery room SUMMARY Histopathological diagnosis of biopsy samples and margin assessment of surgical specimens are challenging aspects in sarcoma. Using dog patient tissues, we assessed the performance of a recently developed technology for fast ex vivo molecular lipid-based diagnosis of sarcomas. The instrument is based on mass spectrometry (MS) molecular analysis through a laser microprobe operating under ambient conditions using excitation of endogenous water molecules. Classification models based on cancer/normal/necrotic, tumor grade, and subtypes showed a minimum of 97.63% correct classification. Specific markers of normal, cancer, and necrotic regions were identified by tandem MS and validated by MS imaging. Real-time detection capabilities were demonstrated by ex vivo analysis with direct interrogation of classification models.

This Protocol describes SpiderMass, a novel platform for in vivo and real time mass spectrometry analysis. The Procedure describes system setup and calibration, analysis of cell culture, tissue section and in vivo skin samples, and data processing. TWEET A new Protocol for in vivo and real time ambient mass spectrometry analysis of cultured cells, tissue sections, and in vivo skin. COVER TEASER In vivo and real-time ambient MS surface analysis Primary research articles where the protocol has been used and/or developed: